METHOD FOR IMPROVING A PIPERAZINE COLOUR STABILITY

摘要

The invention relates to a method for improving a piperazine post-cleaning colour stability consisting in producing a piperazine aqueous solution by introducing a solid or liquid piperizine whose degree of purity is equal to or greater than 90 % by weight into water, in removing water by distillation and in separating the piperazine having a maximum predetermined water content. The aim of said invention is also to develop a rapid ageing test which enables to control the improvement of the colour stability.